This is far from the first attempt to use a water-based, chemical approach to processing copper. Today, some copper ore is processed with acid, for example, and Ceibo, a startup based in Chile, is trying to use a version of that process on the type of copper that’s traditionally smelted. The difference here is the particular chemistry, particularly the choice to use vanadium.
One of Still Bright’s founders, Jon Vardner, was researching copper reactions and vanadium flow batteries when he came up with the idea to marry a copper extraction reaction with an electrical charging step that could recycle the vanadium.
COURTESY OF STILL BRIGHT
After the vanadium reacts with the copper, the liquid soup can be fed into an electrolyzer, which uses electricity to turn the vanadium back into a form that can react with copper again. It’s basically the same process that vanadium flow batteries use to charge up.
While other chemical processes for copper refining require high temperatures or extremely acidic conditions to get the copper into solution and force the reaction to proceed quickly and ensure all the copper gets reacted, Still Bright’s process can run at ambient temperatures.
One of the major benefits to this approach is cutting the pollution from copper refining. Traditional smelting heats the target material to over 1,200 °C (2,000 °F), forming sulfur-containing gases that are released into the atmosphere.
Still Bright’s process produces hydrogen sulfide gas as a by-product instead. It’s still a dangerous material, but one that can be effectively captured and converted into useful side products, Allen says.
Another source of potential pollution is the sulfide minerals left over after the refining process, which can form sulfuric acid when exposed to air and water (this is called acid mine drainage, common in mining waste). Still Bright’s process will also produce that material, and the company plans to carefully track it, ensuring that it doesn’t leak into groundwater.
The company is currently testing its process in the lab in New Jersey and designing a pilot facility in Colorado, which will have the capacity to make about two tons of copper per year. Next will be a demonstration-scale reactor, which will have a 500-ton annual capacity and should come online in 2027 or 2028 at a mine site, Allen says. Still Bright recently raised an $18.7 million seed round to help with the scale-up process.
How scale up goes will be a crucial test of the technology and whether the typically conservative mining industry will jump on board, UNR’s Jowitt says: “You want to see what happens on an industrial scale. And I think until that happens, people might be a little reluctant to get into this.”